BFE coding challenge #1 implement curry()

https://bfe.dev is like a LeetCode for FrontEnd developers. I’m using it to practice my skills.

This article is about the coding problem #1 implement curry()

First let’s decide the input and output of our function from the examples.

const  join = (a, b, c) => {
   return `${a}_${b}_${c}`
}

const curriedJoin = curry(join)

curriedJoin(1, 2, 3) // '1_2_3'

curriedJoin(1)(2, 3) // '1_2_3'

curriedJoin(1, 2)(3) // '1_2_3'

Obviously curry() should return a function, which accepts arbitrary arguments, and do the following:

1. if arguments are enough, call join and return the result
2. if not enough, then return a new function which does 1. Key is above point 2.

curriedJoin(1,2) should return a new function, which will insert 1,2 before the argument 3 , this could be done by Function.prototype.bind()

function curry(func) {
  return function curried(...args) {
    // 1. if enough args, call func 
    // 2. if not enough, bind the args and wait for new one
    if (args.length >= func.length) {
      return func.apply(this, args)
    } else {
      return curried.bind(this, ...args)
    }
  }
}

Ok, passed!

Hope it helps. See you next time.